1. Field of the Invention
The present invention relates to parting compositions for foodstuffs and, in-particular, to lecithin/edible oil parting compositions which may be free of monohydric aliphatic alcohols such as ethyl alcohol. The parting composition of the invention may be dispensed from conventional aerosol spray cans to provide a smooth, clear coating on the cooking surfaces of cooking utensils.
2. Background and Related Art
The prior art has devoted considerable effort to providing lecithin-containing food parting compositions which do not discolor foodstuffs or impart undesirable flavors to them, and which may be applied to the cooking surfaces of cooking utensils from a conventional pressurized aerosol dispenser in a clear, smooth, i.e., non-foaming, coating.
The coating, which may be used in lieu of oils, grease, butter, etc., to lubricate the food-contacting surfaces of cooking utensils such as frying and baking pans, facilitates separation of the cooked foodstuffs from the cooking surfaces. The use of lecithin is of course well known for this purpose and conventional food release compositions comprise a mixture of lecithin, a naturally-occurring substance usually derived from soybean oil, an edible oil and other known additives.
One approach taken by the prior art is to incorporate ethanol, i.e., ethyl alcohol, in a lecithin-vegetable oil mixture which is pressurized by a suitable propellant gas such as a hydrocarbon gas. This approach is exemplified in U.S. Pat. No. 4,188,412 of V. D. Sejpal, which provides for the inclusion of 7.5 to 25 percent by weight of ethyl alcohol (190.degree. to 200.degree. proof) in a lecithin-vegetable oil mixture which is pressurized by a hydrocarbon propellant for aerosol dispensing. This composition is stated to provide a suitably low viscosity for the mixture in a uniform, one-phase system, and renders even high concentrations of lecithin in the composition suitable for dispensing from aerosol containers in a clear, non-foaming manner. The ethyl alcohol is described as reducing the viscosity of the mixture and acting as an emulsifier (column 2, lines 11-32). The Patentee states that the stated limits for ethyl alcohol are critical to avoid undesirable foaming characteristics of the product and that 190.degree. proof alcohol can be substituted for 200.degree. proof alcohol. At the described critical range of 7.5 to 25 percent alcohol, the use of 190.degree. proof alcohol will introduce 0.57 to 1.9 percent moisture into the composition. (See columns 11-12 of the Patent.)
U.S. Pat. No. 4,142,003 to Sejpal discloses non-aerosol vegetable oil compositions containing lecithin and 1 to 15 percent by weight ethyl alcohol. In TABLE 4 of the Patent, two sets of formulations comprising, variously, 3 or 12 percent lecithin, 82 or 73 percent soybean oil and 1 or 15 percent ethyl alcohol of from 50.degree. to 190.degree. proof are disclosed. The Patentee notes (column 4, lines 1-3) that 180.degree. and lower proof alcohols cannot be utilized, presumably because of the resulting excess water content. TABLE 4 shows that use of lower proof alcohols results in separated, unclear products. At column 4, lines 7-33, the Patentee discloses upper limits for the amount of water introduced by the alcohol when 190.degree. proof ethyl alcohol is used. The upper limit is given as about 0.60 percent by weight of water for a vegetable oil-ethyl alcohol formulation containing 12 percent by weight of lecithin, and about 0.4 percent by weight of water if the formulation contains 3 percent by weight of lecithin. The Patentee continues to note that "Within these critical limits, ethyl alcohol of somewhat less than 190.degree. proof may be utilized in reduced amounts." Because of these stringent upper limits on the amount of water which can be tolerated in the composition, the Patentee states that " . . . it is preferred that the ethyl alcohol be at least 190.degree. proof."
U.S. Pat. No. 4,163,676 issued to K. S. Konigsbacher discloses a pump-dispensable lecithin-based parting composition which comprises lecithin in an essentially anhydrous vehicle consisting essentially of a monohydric aliphatic alcohol having two or three carbon atoms, i.e., ethyl alcohol or propyl alcohol, and vegetable oil in proportions to provide a pump-sprayable consistency. This Patentee discloses that the presence of water tends to aggravate consistency problems and is desirably minimized in the composition to provide a maximum water content below that amount which forms a constant boiling mixture with the alcohol being used. (See column 1, line 59 to column 2, line 3 of the Patent.)
Another approach demonstrated in the prior art to attain the objective of a dispensable (by aerosol or otherwise) composition which provides a smooth, clear coating is to employ a water-in-oil emulsion of lecithin as exemplified in U.S. Pat. No. 3,896,975 to D. W. Follmer. Follmer discloses such a composition utilizing three major types of naturally-occurring lecithin so as to have a hydrophile-lipophile balance number ("HLB") of not more than seven. (The HLB number is defined at column 4, line 52 et seq of the Patent.) The water-in-oil emulsion of the Follmer Patent may also comprise so-called "edible detergents" (column 6, lines 56 through column 7, line 6). The "edible detergents" include glycerol monostearate, glycerol monooleate, propylene glycol monolaurate and polyethylene glycol fatty acid esters such as polyethylene glycol monolaurate, among others. The composition may be dispensed from a pressurized container through the use of a propellant (column 7, lines 7-23).
U.S. Pat. No. 3,661,605 issued to L. R. Rubin et al discloses an aqueous aerosol composition comprising a homogenized dispersion of hydroxylated lecithin in water. The Follmer Patent, described above, states at column 1, line 62 et seq that the use of hydroxylated, adulterated lecithin was resorted to in the Rubin et al Patent in order to obtain mixing of the lecithin with water adequate to prepare a water-based system. The Follmer Patent also states (column 1, line 41 et seq) that " . . . lecithin is uniquely effective, if not chemically adulterated as by hydroxylation to lose lubricity, because in addition to its lubrication qualities it is a naturally occurring material . . . ".
Other examples of water-in-oil/lecithin emulsions for use as food parting compositions include U.S. Pat. Nos. 4,073,411 and 4,073,412 to C. Doumani.
Another composition containing water as a major component is shown in Japanese Patent J5 4038-282 dated Mar. 22, 1979 which appears (from its English language Abstract) to disclose a scorch inhibitor comprising 6 to 55 percent edible oil, 1 to 48 percent lecithin, 40 to 94 percent water and 0.1 to 4 percent of a polyhydric alcohol, which together constitute the base preparation.
U.S. Pat. No. 4,371,451 to Scotti et al.dated Feb. 1, 1983, discloses lecithin-containing surface release compositions comprising 7 to 60 percent water, 3 to 15 percent lecithin and 30 to 85 percent dimethylether, which serves as the propellant.
It is a known practice in the production of commercial lecithin to add limited quantities of free fatty acids as thinning agents to reduce the viscosity of the lecithin and to standardize the pH of the lecithin product.